Catalyst structure and method of fischer-tropsch synthesis

Abstract

The present invention includes Fischer-Tropsch catalysts, reactions using Fischer-Tropsch catalysts, methods of making Fischer-Tropsch catalysts, processes of hydrogenating carbon monoxide, and fuels made using these processes. The invention provides the ability to hydrogenate carbon monoxide with low contact times, good conversion rates and low methane selectivities. In a preferred method, the catalyst is made using a metal foam support.

We claim:  
     
       1. A catalyst structure for Fischer-Tropsch synthesis, comprising: 
       a porous structure with a pore surface area and a pore size of at least about 0.1 μm;  
       wherein the porous structure comprises a honeycomb, felt, foam or wad;  
       a buffer layer disposed on said porous structure;  
       a porous interfacial layer with a pore surface area and a pore size less than the pore size of the porous structure, said porous interfacial layer disposed upon said buffer layer;  
       a Fischer-Tropsch catalyst selected from the group consisting of cobalt, ruthenium, iron, rhenium, nickel, osmium and combinations thereof placed upon said pore surface area of said porous interfacial layer.  
     
     
       2. The catalyst structure as recited in  claim 1 , wherein said porous structure has a geometry selected from the group of foam, felt, wad and combinations thereof. 
     
     
       3. The catalyst structure as recited in  claim 2 , wherein said porous structure is of a material selected from the group consisting of metal, ceramic and combinations thereof. 
     
     
       4. The catalyst structure as recited in  claim 1 , wherein said porous interfacial layer is selected from the group consisting of γ-Al 2 O 3 , SiO 2 , ZrO 2 , TiO 2 , magnesium oxide, vanadium oxide, chromium oxide, manganese oxide, iron oxide, nickel oxide, cobalt oxide, copper oxide, zinc oxide, molybdenum oxide, tin oxide, calcium oxide, aluminum oxide, lanthanum series oxide(s), zeolite(s) and combinations thereof. 
     
     
       5. A reactor comprising the catalyst structure as recited in  claim 1 , wherein the catalyst structure is disposed in a reaction chamber, said reaction chamber having walls defining a microchannel through which pass reactants. 
     
     
       6. A reactor comprising a reaction chamber and at least one cooling chamber, and the catalyst structure as recited in  claim 1 , wherein the catalyst structure is disposed in said reaction chamber, said reaction chamber having walls that separate said reaction chamber from at least one cooling chamber. 
     
     
       7. The catalyst structure as recited in  claim 1 , wherein said buffer layer is selected from the group consisting of Al 2 O 3 , TiO 2 , SiO 2 , and ZrO 2  and combinations thereof. 
     
     
       8. The catalyst structure as recited in  claim 1 , wherein said buffer layer includes a sublayer of titania. 
     
     
       9. A Fischer-Tropsch reactor comprising the Fischer-Tropsch catalyst structure recited in  claim 1 . 
     
     
       10. The catalyst of  claim 1  wherein the porous structure has a pore size of 10 μm to 300 μm. 
     
     
       11. The catalyst of  claim 1  wherein the catalyst possesses catalytic activity such that, if the catalyst is placed inside an isothermal furnace and exposed to a feed stream consisting of a 3 to 1 ratio of hydrogen gas to carbon monoxide, at 250° C., at 6 atm, at a contact time less than 5 seconds and the product stream is collected and cooled to room temperature, the selectivity to methane is less than 25% and the carbon monoxide conversion is greater than 25%. 
     
     
       12. The catalyst of  claim 1  wherein the porous structure has a porosity of 60 to 98%. 
     
     
       13. The catalyst of  claim 1  wherein the porous structure is a metal foam. 
     
     
       14. The catalyst of  claim 13  wherein the metal foam comprises 20 to 3000 pores per inch. 
     
     
       15. The catalyst of  claim 1  wherein the Fischer-Tropsch catalyst is selected from the group consisting of cobalt, ruthenium, iron, rhenium, osmium and combinations thereof. 
     
     
       16. The catalyst of  claim 11  wherein the interfacial layer has a depth of less than 50 μm. 
     
     
       17. The reactor of  claim 6  wherein the catalyst has contiguous material and contiguous porosity such that molecules can diffuse through the catalyst, and the catalyst is disposed in the reaction chamber such that gases will flow substantially through the catalyst. 
     
     
       18. The reactor of  claim 17  wherein the cross-sectional area of the catalyst occupies at least 80% of the cross-sectional area of the reaction chamber. 
     
     
       19. The reactor of  claim 17  wherein the cross-sectional area of the catalyst occupies at least 95% of the cross-sectional area of the reaction chamber. 
     
     
       20. The reactor of  claim 6  wherein the cooling chamber comprises a microchannel.